Device and method for mixing of a multi-component cement

ABSTRACT

A manually drivable device for the mixing of a pasty mixing ware from at least two fluid starting components comprising at least two cartridges having feed plungers; a mixing space to mix the starting components, mixing vanes being provided in the mixing space and mounted such that they can rotate; a lever rotatable about a pivot point operatable manually or a pin that can be shifted in longitudinal direction and operatable manually in order to operate the device; a gear connected to the lever or pin, and connected to the rotatable mixing vanes in the mixing space; and a facility for propelling the feed plungers such that the motion of the lever or pin drives the rotation of the mixing vanes in the mixing space and motion of the feed plungers into the cartridges. The invention also relates to a method for mixing fluid starting components using the device.

This application claims priority of German Patent Application No. 102014 106 873.4, filed May 15, 2014, the disclosure of which isincorporated herein by reference.

DESCRIPTION

The invention relates to a manually drivable device for the mixing of apasty mixing ware from at least two fluid starting components, inparticular for mixing a medical cement, and, if applicable, for storageof the starting components.

The invention also relates to a method for mixing fluid startingcomponents and, if applicable, also for dispensing a mixing ware, inparticular for mixing a medical cement.

Specifically, also a subject matter of the invention is a device forstoring and mixing polymethylmethacrylate bone cement (PMMA bone cement)that consists, prior to mixing and during storage, of a liquid or pastyfirst component and separate powdery or pasty second component, as wellas a method for mixing the two components, and applying if applicable,the mixed PMMA bone cement and, if applicable, for applying the mixedPMMA bone cement as well as, if desired, an additional pharmaceuticalagent that can be admixed or is added to one of the starting componentsor both starting components.

Polymethylmethacrylate bone cements (PMMA bone cements) have been in usein medicine for decades for permanent mechanical fixation of total jointendoprostheses. These are based on powder-liquid systems, whereby it iscustomary to use methylmethacrylate as monomer. Recently,polymethylmethacrylate bone cements that are based on the use of cementpastes have been proposed as well (DE 10 2007 050 762 B3, DE 10 2008 030312 A1, DE 10 2007 052 116 A1). These bone cements have two cementpastes stored separately in suitable cartridges. Cartridges of this typeare also often referred to as 2-component cartridges (also as2K-cartridges). These each contain components of a redox initiatorsystem, aside from at least one monomer and suitable polymers. Saidstarting components can also be used and applied, preferably, in devicesaccording to the invention and methods according to the invention.

Methylmethacrylate is the monomer used most commonly inpolymethylmethacrylate bone cements. Redox initiator systems usuallyconsist of peroxides, accelerators and, if applicable, suitable reducingagents. Radicals are formed only if all ingredients of the redoxinitiator systems act in concert. For this reason, the ingredients ofthe redox initiator system in the separate starting components arearranged appropriately such that these cannot trigger a radicalpolymerisation. The starting components are stable during storageprovided their composition is adequate. Only when the two startingcomponents are mixed to produce a cement dough, the ingredients of theredox initiator system, previously stored separately in the two pastes,react with each other forming radicals which trigger the radicalpolymerisation of the at least one monomer. The radical polymerisationthen leads to the formation of polymers while consuming the monomer,whereby the cement dough is cured. It is customary to mix the startingcomponents with static mixers, which are attached to the two-componentcartridges filled with the starting components for this purpose.

When the two pasty starting components are extruded from the cartridges,the starting components are pushed through a static mixer. As a result,the processes of extruding and mixing proceed concurrently. Mixing thestarting components in the static mixer requires a high extrusion forcesince the pressure drop at the mixing elements in the static mixer isvery high. As a result, it is necessary to use powerful pneumatic ormechanical extrusion devices to attain the dispensation and optimalmixing of the pasty starting components. Said pneumatic or mechanicalextrusion devices are elaborate from a technical point of view andexpensive. An inexpensive option are the manually-operated extrusionguns, which are customary thus far for use with thepolymethylmethacrylate bone cements based on powder-liquid systems,which are suitable for said cements, but are not sufficiently powerfulfor the extrusion and mixing of bone cement pastes by means of staticmixers.

If the volumes of the starting components to be mixed are unequal and/orthe mixing ratios are very uneven (2:1 and more), very many mixingspirals are required due to the more pronounced volume ratios. Thelarger the number of mixing spirals needed, the larger is the pressuredrop in the static mixer during the mixing process. One pasty componentneeds to be present, whereas the second component can be either liquidor powdery or pasty as well. The components and/or pastes need to bepressed through the static mixer by a very large force. Due to thenature of manually-operated extrusion devices, the maximally possibleextrusion force is limited.

The Semkit® system is time-proven in the adhesives and sealants industryfor many years. In this system, a paste is stored in a storagecontainer. A second liquid component is present in a stirring rod,separated from the paste through a valve that is integrated into thestirring rod. Actuating the valve allows the liquid to flow into thepaste which can then be mixed by hand.

One disadvantage of a system of this type is that multiple steps arerequired to get the mixing ware, in particular the medical cement, readyfor use. Another disadvantage of the known systems is that simple manualoperation of the devices enabling the mixing and dispensation of thepasty masses is not feasible. This is a particularly major disadvantagein the often hectic and stressful operation during a surgicalintervention in a patient, i.e. during medical use. Accordingly, itwould be desirable to have a device for mixing of the startingcomponents that can be operated more easily and by hand. Since systemsoperated with compressed air and/or an electric motor require expensivecomponents, the system can no longer be used as a hygienic article forsingle use.

For pasty polymethylmethacrylate bone cements, solid cartridges ofstable shape are required, since the relatively viscous pastypolymethylmethacrylate bone cement dough and/or the pasty startingcomponents can be extruded from storage containers and/or cartridgesonly through very large extrusion forces. Moreover, it is not feasibleto use mixing systems for with bone cements, in which an inadvertentexit of small amounts of paste takes place and in which there is apossibility that air is drawn into the paste. This would not only impairthe cleanliness in the operating theatre, but would also mechanicallyweaken the cement dough through the introduction of air since airbubbles in the cured cement act as fissure initiation sites and thusreduce the stability of the cured bone cement. Therefore, the Semkit®system cannot be used for pasty polymethylmethacrylate bone cements.

Accordingly, it is the object of the invention to overcome thedisadvantages of the prior art. Specifically, aninexpensive-to-manufacture and reliably-working device for the mixing ofa pasty mixing ware, in particular a medical cement, from at least twofluid starting components and, if applicable, for storage of thestarting components, and a method for the mixing of the pasty mixingware is to be devised, in which the simplest manual operation can beused to mix fluid starting components that are stored separate from eachother in cartridges, in particular of highly viscous and/or viscouspastes without having to use an external or additional energy source andwithout air inclusions arising in the mixing ware.

Specifically, a simple and inexpensive device for the storing and mixingof polymethylmethacrylate bone cement is to be developed that can beused to store at least one starting component in the absence of air,whereby it shall be feasible, through the use of the device, to mix thestarting components and preferably to also dispense the cement dough.

The main component of the polymethylmethacrylate bone cement, as mixedware, shall be a cement paste and the second component can also be pastyor be present in the form of a powder. It shall be possible to store thetwo starting components of the bone cement separate from each other andto combine them safely by using the device.

The objects of the invention are met by a manually-drivable device forthe mixing of a pasty mixing ware from at least two fluid startingcomponents, in particular for the mixing of a medical cement,comprising:

A) at least two cartridges containing the fluid starting components orat least two connectors for at least two cartridges containing the fluidstarting components, whereby feed plungers are provided in thecartridges for expelling the starting components from the cartridges;

B) a mixing space for the mixing of the starting components that isconnected to the cartridges or connectors for the cartridges such thatthe starting components are guided into the mixing space when thestarting components are expelled from the cartridges by the feedplungers, whereby mixing vanes are provided in the mixing space and aremounted in the mixing space such that they can rotate;

C) a lever that can be rotated about a pivot point and can be operatedmanually for operation of the device or a pin that can be shifted inlongitudinal direction and can be operated manually in order to operatethe device;

D) a gear connected to the lever or pin, whereby the gear isappropriately connected to the rotatable mixing vanes in the mixingspace such that the mixing vanes can be rotated in the mixing space upona motion of the lever or pin mediated by the gear; and

E) a facility for propelling the feed plungers in the cartridges,appropriately connected to the lever or pin such that the feed plungerscan be propelled in the cartridges upon a motion of the lever or pin,such that the motion of the lever or pin drives the rotation of themixing vanes in the mixing space and the motion of the feed plungersinto the cartridges.

Referring to attachable cartridges, it is self-evident that the facilityis suitable for propelling the feed plungers in the attached cartridges,whereby the facility is connected to the lever or pin such that the feedplungers can be propelled in the attached cartridges upon a motion ofthe lever or pin.

In particular and particularly preferably according to the invention,the device is a cementing gun.

According to the invention, the starting components for the mixing ware,in particular for the bone cement, are already present in thecartridges.

It is particularly preferred according to the invention that the deviceis also well-suited for the storage of the starting components, inparticular when the cartridges are inserted into the device or thecartridges are a fixed part of the device.

Conceivable fluid starting components are liquid, pasty, i.e.paste-like, and fluid powdery starting components. At least one of thestarting components is pasty or liquid in order to obtain a pasty mixingware. Preferably, both starting components are pasty.

The mixing ware is particularly preferred to be a bone cement, inparticular a PMMA bone cement.

Preferably, the cartridges have one opposite opening in each cartridgeprovided opposite from the feed plungers for expelling the startingcomponents from the cartridges, whereby the starting components are tobe guided through said openings from the cartridges into the mixingspace.

It is also preferred for the invention to provide the motion of thelever or pin, by means of which the mixing vanes can be rotated in themixing space by means of the gear and by means of which the feedplungers are propelled in the cartridges, to be a manually drivenmotion.

It can also be preferred to arrange on the lever or pin a restoringelement, such as a compression spring, by means of which the lever orpin can be returned to its starting position after lever or pin is movedby hand. It is particularly preferable to have the restoring element gettensioned or compressed while the lever and/or pin is moved by hand.

Devices according to the invention can be provided appropriately suchthat the mixing vanes are inclined consistently with respect to the axisabout which the mixing vanes rotate in the mixing space such that therotation of the mixing vanes in the mixing space causes the mixing wareto be propelled in the mixing space, whereby the mixing vanes arepreferred to be inclined with respect to the axis by the same angle.

It is preferred, but not mandatory, to have all mixing vanes be inclinedwith respect to the axis. In this context, consistently shall beunderstood to mean that the mixing vanes are inclined by the same anglewith respect to the axis about which the mixing vanes rotate.Accordingly, opposite mixing vanes are not arranged to bemirror-symmetrical, but to be rotationally-symmetrical with respect tosaid axis. The mixing vanes thus form a propeller or a turbine bladeconfiguration.

As a result, the mixing vanes can be used well for both the mixing ofthe mixing ware and/or the mixing of the two starting components and forpropelling the mixing ware in the mixing space. This also enables theuse of viscous and/or highly viscous pastes as starting components inthe manual force-driven device.

Preferred refinements of the device according to the invention can becharacterised in that the gear is force-locking and/or form-fitting.

Gears of this type are particularly well-suited for transmission of theforces exerted by hand. The gear can preferably have little or no play.

A refinement of the present invention proposes the gear to comprise atleast one tooth lock washer, at least one friction disk, at least onecogwheel, at least one worm wheel and/or at least one friction wheel bymeans of which the force and/or torque is transmitted. Preferably, thegear comprises at least one conical tooth lock washer, at least oneconical friction disk, at least one conical cogwheel and/or at least onefriction wheel for changing the direction of rotation.

Said components can be manufactured easily and inexpensively at therequisite stability even from plastic material. The use of forcetransmission elements of a conical design is advantageous in that thedirection of the transmitted torque can be changed in the gear.

Preferred refinements of the present invention can provide the gear tobe a cogwheel gear, a friction wheel gear, a conical wheel gear, acontrate gear, a worm gear or a combination of said gears, preferablyadditionally comprising a spur gear.

Friction wheel gears are often referred to as friction gear. The gearcan be driven either via the front surface of the cogwheel or frictionwheel (normal design) or via a lateral surface on the edge of thecogwheel or friction wheel (lateral surface teeth or lateral surfacefriction). Said gears are easy and inexpensive in design, well-suitedfor the requisite transmission of force and torque, and not prone tofailure in operation.

According to a particularly preferred refinement, the present inventioncan provide the mixing vanes to be arranged on a rotary shaft (in themixing space) mounted such as to be rotatable, whereby the rotary shaftextends out of the mixing space, preferably extends out of the mixingspace via a seal, and the rotary shaft is connected to the gear suchthat the rotary shaft with the mixing vanes can be rotated in the mixingspace by means of a motion of the lever or pin.

This is advantageous in that, firstly, the design is particularlysimple, and, additionally, the central axis of the mixing space isfilled by the rotary shaft such that no poorly mixed parts of the mixingware can be pressed through in this location.

Moreover, the invention can preferably provide a clutch in theconnection of the gear to the mixing vanes, in particular in the rotaryshaft mounted such as to be rotatable, or in the gear, whereby theclutch allows the mixing vanes to rotate in one direction of rotationand prevents or reduces rotation in the opposite direction of rotation.

As a result, the mixing vanes rotate in one direction only or mainly inone direction. If the mixing vanes are also utilised to propel themixing ware, this prevents the mixing vanes from rotating in reversedirection during the reverse motion of the lever or pin and thus frominadvertently conveying the mixing ware back in the direction of thecartridges.

In this context, the invention can provide a free-wheel clutch on or inthe gear or provide a sprung rotating clutch in the connection from thegear to the mixing vanes, in particular in the rotary shaft mounted suchas to be rotatable.

Sprung rotating clutches of this type, which are presently also referredto as free-wheel clutches, are known, for example, from ballpoint pensand can be manufactured very inexpensively, while their function issufficient for the application according to the invention. In sprungrotating clutches of this type, a serrated circular surface engages amatching counterpart, whereby the two circular surfaces are pressed ontoeach other by means of an elastic spring. The serration has a steepflank in one direction of rotation, preferably a perpendicular flank,and a shallow flank in the other direction of motion. When the drivencircular surface rotates in the direction of the steep flank, the othercircular surface rotates along, since the steep flanks engage eachother. Upon a rotation in the reverse direction, the shallow flanksslide over each other and the other circular surface does not rotatealong due to slip. As a result, the rotation of the shaft is transmittedto the mixing vanes in one direction only.

As a result, what this attains, in easy and inexpensive manner, is thatthe mixing vanes rotate in one direction only and cannot rotate in theopposite direction upon restoration or reverse motion of the lever orpin and cannot inadvertently push the mixing ware in the mixing space inthe direction of the cartridges.

According to the invention, the facility for propelling the feedplungers in the cartridges can be a mechanical propelling facility. Thismakes the design of the device simple.

A refinement of the present invention proposes that the facility forpropelling the feed plungers in the cartridges is a clamp rod having atiltable jamming opening or a gear rack having a unidirectionally-actingsnap-in locking means, whereby the jamming opening or the snap-inlocking means is connected to the lever or the jamming opening or thesnap-in locking means is connected to the pin, in particular the jammingopening or the snap-in locking means is connected to the pin via alever.

The facility for propelling the feed plungers in the cartridges can alsobe designed to include a spindle. As a result of the measures specifiedabove, the feed plungers can be propelled step-by-step by multipleoperation and/or multiple strokes of the lever or pin. As a result, evenmajor quantities of the mixing ware can be mixed by hand from viscous orhighly viscous pastes such as is required, for example, in the case ofbone cements. Jamming openings of this type are known, for example, fromcartridge guns for silicone.

In order to enable extended storage of the starting components in thedevice, the invention can provide at least one manually-opening valveelement or manually-opening closures to be arranged in the connectionbetween the mixing space and the cartridges or in the connectors for thecartridges.

As a result, the facility can also be used well for storage of thestarting components since the starting components in the cartridges areclosed off by the cartridge walls versus the outside, on one side by thefeed plungers, and on the opposite side by the closures or the valveelement. As a result, the content stays sterile and does not dry out soreadily during storage.

It is preferred to use, as valve element, an axially rotatablecylindrical tube section that touches against the cylindrical internalwalls of the mixing space, whereby two bushings are arranged in thejacket surface of the tube section, whereby the bushings can be made tooverlap with the connections to the cartridges by rotating the tubesection. The overlapping of the bushings and connections to thecartridges causes the valve element to be open. When the bushings aremade to overlap with connection openings to the cartridges, the valveelement is in an opened position. Said design is simple and inexpensiveto manufacture from plastics and its operation is not error-prone. It isparticularly preferred to have an operating lever fastened to the tubesection and the operating lever to extend through an opening in the wallof the mixing space, in particular through a radial slit in the wall ofthe mixing space. As a result, the tube section can be manually rotatedin the mixing space and can thus be opened and, if desired, closedagain.

A device according to the invention that is particularly easy to operatecan be attained in that the device comprises a handle for holding thedevice by one hand, whereby the lever or the pin or an operating elementfor manual operation of the lever or pin is arranged appropriately inthe region of the handle such that the lever or pin or operating elementcan be operated by the same hand that holds the device by the handle.

As a result, the device can be operated by one hand. This simplifiesmanual operation.

Preferred devices according to the invention can be characterised inthat the mixing space comprises a dispensing opening for application ofthe mixing ware on the side opposite from the connection to thecartridges, whereby it is preferred to have an application tubeconnected or be connectable to the dispensing opening.

As a result, the mixing ware can be applied and/or dispensed and useddirectly by the device.

A refinement of the present invention also proposes static shearingelements for mixing of the mixing ware to be arranged in the mixingspace, whereby it is preferred that said shearing elements cut the flowof the mixing ware through the mixing space and/or that the shearingelements are arranged in axial direction relative to the axis aboutwhich the mixing vanes rotate, between the mixing vanes.

The use of shearing elements cutting through the mixing ware in thefeeding direction attains more vigorous mixing of the mixing ware.

A refinement of the invention also proposes a circular arc or circulararc section to be arranged on said lever and to have on its front faceor its side surface a driving row of cogs or a friction surface arrangedby means of which a cogwheel or friction wheel of the gear can be drivenor that a serration or a friction surface is arranged on the pin bymeans of which a cogwheel or friction wheel of the gear can be driven.

The driving row of cogs or friction surface can also be inclined withrespect to the front face or side surface of the circular arc orcircular arc section. In addition or alternatively, the gear wheel orfriction wheel of the gear driven by the row of cogs or friction surfacecan be a bevel gear wheel.

Due to the use of a circular arc with the lever, the tilting motion ofthe lever can be directly converted into a rotational motion of thecircular arc by means of which the gear is being driven. Said design isinexpensive to implement and simple and not malfunction-prone.

Particularly advantageous refinements of the invention can becharacterised in that the gear comprises an appropriate transmissionratio such that, upon a full motion of the lever or pin, the mixingvanes perform at least 2 turns in the mixing space, preferably performbetween 2 and 10 turns in the mixing space, particularly preferablybetween 2.5 and 5 turns in the mixing space.

If said transmission ratios are selected, one stroke is sufficient forsufficient mixing and sufficient propulsion of the mixing ware in themixing space even in the case of highly viscous and very viscous pastesas starting components without the manual force of a normal user nolonger being enough to operate the device manually, in particular by onehand.

Moreover, the invention can provide the facility for propelling the feedplungers in the cartridges to be appropriately connected to the lever orpin such that, upon a full motion of the lever or pin, the feed plungersare propelled in the cartridges by at least 1 mm, preferably arepropelled in the cartridges by between 2 mm and 12 mm, particularlypreferably are propelled in the cartridges by between 5 mm and 7 mm.

At this level of propulsion, which preferably is selected to match therotating speed of the mixing vanes in the mixing space, the startingcomponents can still be dispensed from the cartridges even in the caseof viscous and/or highly viscous starting components.

Particularly preferred embodiments of the invention can provide thefacility for propelling the feed plungers in the cartridges to beappropriately connected to the lever or pin such that the feed plungersexpel at least 90% of the starting components from the cartridges upon 5to 25 full motions of the lever or pin, preferably such that the feedplungers expel at least 90% of the starting components from thecartridges upon 10 to 20 full motions of the lever or pin.

As a result, the device is very useful, in particular, for mixing andapplying bone cement. The motion cycles as specified can be performedwithout too much effort without fatigue to the arm and/or hand of theuser, but also in a manner such that each individual motion, i.e. eachindividual stroke of the lever or pin, does not require too much force.

The device is preferred to consist of plastics, particularly preferablyof thermoplastics, with the exception of restoring elements and/orspring elements. It is even more particularly preferred to have therestoring elements and/or spring elements also consist of plastics.

According to the invention, the device is encased by a housing such thatreaching into parts of the device that move during its application,other than the lever or pin, is prevented. The lever or pin are beingoperated in order to use the device and must therefore be accessible tothe user.

The underlying objects of the invention are also met by a method for themixing of fluid starting components and, if applicable, also for thedispensation of a pasty mixing ware, in particular for the mixing of amedical cement, preferably by means of a device as described herein,characterised in that

A) a lever is being tilted or a pin is being moved in longitudinaldirection;

B) the force of the motion of the lever or pin propels feed plungers inat least two cartridges and presses the starting components contained inthe cartridges into a mixing space by means of the feed plungers; and

C) the force of the motion of the lever or pin rotates mixing vanes inthe mixing space, whereby the transmission of the force of the lever orpin for rotation of the mixing vanes is effected by means of a gear.

In this context, the invention can provide the rotation of the mixingvanes in the mixing space to mix the starting components in the mixingspace and convey them in the direction of a dispensing opening.

Due to said concurrent mixing and dispensation, even highly viscous andviscous pastes can be used as starting components for the mixing ware.Concurrently, manual operation of the device and/or manual driving ofthe lever or pin is still sufficient to drive the mixing vanes and thefeed plungers in the device.

A refinement of the invention also proposes that the lever or pin, afterbeing moved, is restored to the starting position by a restoringelement, whereby it is preferred that the feed plungers are not movedand the mixing vanes are not rotated during said restoration to thestarting position.

As a result, the device can be used by multiple strokes of the lever orpin, which allows the force to be applied and the amount of mixing wareproduced per stroke to be adjusted and/or smaller portions to be used.

The invention can just as well provide the gear to be driven by means ofa sprocket wheel or friction sprocket wheel on the lever or a row ofcogs or a friction surface on the pin.

The invention also proposes to repeat the motion of the pin or lever,preferably between 5 and 25 times, in order to empty the cartridges byat least 90%. It is particularly preferred to repeat the motion of thepin or lever 10 to 15 times, in order to empty the cartridges by atleast 90%.

The invention can just as well provide the gear to transmit a fullstroke of the lever or pin into at least 2 turns of the mixing vanes inthe mixing space, preferably into 2.5 to 5 turns of the mixing vanes inthe mixing space.

The invention can provide for the cartridges to be opened towards themixing space, preferably by manual operation of a valve element, priorto the first operation of the lever or pin. This allows the startingcomponents to be stored previously in the cartridges for longer periodsof time.

The invention is based on the surprising finding that, due to themanually-operated lever or pin being connected to both the rotatablemixing vanes and to the facility for propelling the feed plungers in thecartridges, it is feasible to have one stroke of the lever or pin orpreferably multiple strokes of the lever or pin extrude the startingcomponents from the cartridges and concurrently mix the startingcomponents actively. With the mixing vanes in a suitable position, bythe mixing vanes being inclined with respect to the axis about which themixing vanes rotate, and with the direction of rotation of the mixingvanes being appropriate, the rotation of the mixing vanes provides foradditional propulsion of the mixing ware in the mixing space and finallyexpels the mixing ware from a dispensing opening.

Preferably, fixed shearing elements are arranged perpendicular to theconveying direction of the mixing ware in the way of blades between therotating regions of the mixing vanes. When the mixing vanes are drivenin the mixing space via a central rotary shaft, the shearing elementscan be used, additionally, for mounting and positioning the rotary shaftin the mixing space. A central rotary shaft is preferred, since itprevents parts of the mixing ware that are not mixed or poorly mixed inthe axial centre of the mixing space from being conveyed to thedispensing opening and thus from being dispensed from the device.

In order to render the minor rotation (the small angle of rotation) ofthe lever and/or the minor linear stroke of the pin usable for strongmixing by means of the mixing vanes, it has been evident in the scope ofthe invention that a gear can be used in order to transmit the minormotion of the lever or pin into a larger number of turns and a higherangular velocity of the mixing vanes.

But still, and this is in the spirit of the invention, a single strokeof the lever or pin cannot and shall not be sufficient to fully emptythe cartridges. For this reason, it is necessary, during the restorationof the lever or pin, which is preferably attained, according to theinvention, using a restoring element such as a spring, to prevent thefeed plungers from being retracted and to prevent the mixing vanes fromrotating in the reverse direction and thus pushing the mixing ware backin the direction of the cartridges. According to the invention, afree-wheel clutch or any other device for attaining or forcing apreferential direction of rotation is used for the directional rotationof the mixing vanes and is arranged in the connection between the leveror pin and the mixing vanes. In order to prevent a reverse motion of thefeed plungers or facility for driving the feed plungers, a gear rackhaving a unidirectionally-acting snap-in locking means is used, such asare used, for example, in a car lifting jack, or a clamping device isused by means of which a clamp rod is clamped by tilting the clampingdevice and propelled in one direction, while the clamping devicedetaches from the rod upon a reverse motion and thus cannot move the rodin the reverse direction. Said clamping devices are known for cartridgeguns, such as cartridge skeleton guns.

Driving the starting components in and out of the cartridges andconcurrently driving the mixing ware in the mixing space by means of agear allows even very viscous and highly viscous pasty cements andcement components to still be extruded and mixed by hand. In the deviceaccording to the invention and the method according to the invention,the energy for mixing of the starting components no longer needs to bederived from the force of the propulsion of the starting components outof the cartridges. Rather, the mixing ware is mixed by the active motionof the mixing vanes and, preferably, is propelled by the mixing vanesbeing in a suitable position. The force for mixing therefore no longerneeds to be derived from the hydrostatic pressure of the startingcomponents, but rather is transferred directly in the mixing space fromthe mixing vanes to the mixing ware.

Due to the presence of the gear, the minor stroke of the lever or pincan be used to enable strong mixing and strong propulsion by means of arelatively rapid rotation of the mixing vanes.

A preferred manually-operable device according to the invention iswell-suited for the storage and mixing of starting components of amedical cement, in particular of a PMMA bone cement, and, moreover, iswell-suited for application of the mixed medical cement and can, forexample, be designed to have multiple cartridges (preferably twocartridges) with a cylindrical internal space, whereby each cartridgehas a cylindrical feed plunger arranged in it that closes the internalspace of the cartridge and is axially mobile, by means of which thestarting components can be expelled from the internal space of thecartridge. In this context, the starting components are guided into amixing space through an opening that is situated opposite from the feedplungers. In this location, the starting components are mixed andpropelled by rotating mixing vanes. Finally, the mixed mixing ware isexpelled in the front through a dispensing opening or, preferably,through an application tube or dispensing tube, and applied. A leverarranged in the region of a pistol handle is used to operate the device.The device is arranged in a housing that is enclosed except for thedispensing opening or the connector for the dispensing tube and exceptfor a bushing for the lever. The lever is connected to a clamping devicefor unidirectional propulsion of a rod. The rod is connected to a yokeby means of which the feed plungers are propelled in the cartridges. Theyoke is either long enough to still reach the rear-side walls of thecartridges when the feed plungers are propelled fully in the directionof the openings to the mixing space, or the yoke comprises cutting edgesthat cut through the walls of the cartridges when the feed plungers arebeing propelled. The clamping device engages the rod when the lever ismanually pulled towards the pistol handle by closing the hand, whichalso holds the pistol handle, and moves the rod with the yoke and thusthe feed plungers into the cartridges, which pushes the startingcomponents into the mixing space. If the lever was returned into thestarting position by a restoring element, which was tensioned when thelever was pressed, the clamping device detaches and is moved against therod such that the rod and the yoke can no longer be moved backwards anddetach from the feed plungers.

The same motion of the lever also rotates a sprocket that is arranged tobe concentric about the pivot of the lever. The cogs of the sprocket areengaged by a first small gear wheel, whose rotary shaft is connected toa larger gear wheel that has a larger diameter and more cogs than thesmall gear wheel. The friction cogwheels can be implemented by conicalcogwheels or crown gears in order to change the direction of rotation ofthe drive shaft of the mixing vanes with respect to the direction ofrotation of the lever. A free-wheel clutch and/or a sprung rotatingclutch is arranged in the drive shaft that forms the rotary shaft of themixing vanes. Said clutch will be able to be moved in one direction onlyon the side of the rotary shaft facing the mixing vanes such that themixing vanes can be moved in the mixing space in one direction only. Inthis context, the mixing vanes are inclined appropriately with respectto the rotary shaft in the mixing space such that the mixing ware in themixing space is driven in the direction of the dispensing opening.

Frictions wheels can be used just as well as an alternative to theembodiment comprising cogwheels.

The polymethylmethacrylate bone cements that are preferred to be used asmixing ware in devices and methods according to the inventionparticularly preferably use methylmethacrylate as monomer and thus use apowder or a paste containing methylmethacrylate as a first startingcomponent. Matching redox initiator systems usually consist ofperoxides, accelerators and, if applicable, suitable reducing agents,which, according to the invention, are present in the second startingcomponent. Radicals are formed only if all ingredients of the redoxinitiator systems act in concert. For this reason, the startingcomponents of the redox initiator system are arranged appropriately inthe cement pastes, which are separated by the spatially separatedcartridges, such that they cannot trigger a radical polymerisation. Theseparation is attained by the valve element or the closures or any otherseparating device that can be opened, by means of which the startingcomponents can be separated reliably. The starting components are thusstable during storage provided the composition and the selection of thecartridge material are appropriate. Only when the starting componentsare mixed to produce a cement dough as mixing ware, the ingredients ofthe redox initiator system, previously stored separately in the twostarting components, react with each other forming radicals whichtrigger the radical polymerisation of the at least one monomer. Theradical polymerisation then leads to the formation of polymers whileconsuming the monomer, whereby the cement dough is cured (in particularafter application of the cement dough). A dynamic mixer, i.e. mixingvanes rotating in the mixing space, are used to mix the startingcomponents and to propel the cement dough.

BRIEF DESCRIPTION OF THE DRAWINGS

Further exemplary embodiments of the invention shall be illustrated inthe following on the basis of five schematic figures, though withoutlimiting the scope of the invention. In the figures:

FIG. 1: shows a schematic perspective view of a device according to theinvention folded open;

FIG. 2: shows a schematic perspective partial view of a device accordingto the invention;

FIG. 3: shows a schematic perspective partially sectioned view of adevice according to the invention;

FIG. 4: shows another schematic perspective partially sectioned view ofa device according to the invention; and

FIG. 5: shows a schematic side view of a part of another deviceaccording to the invention.

Identical or similar components are identified in the figures, to someextent, through the same reference numbers even if different cementingguns are concerned.

FIG. 1 shows a schematic perspective view of a device 1 according to theinvention that is opened towards the top. The device 1 comprises a lever2 that can be pulled and is arranged in front of a pistol handle 3. As aresult, the device 1 can be held in one hand and the lever 2 can beoperated with the same hand that pulls and/or operates the lever 2. Thelever 2 is supported like in a bearing with respect to the handle 3 suchthat it can rotate about an axis, whereby an elastic compression spring(not shown) is arranged between lever 2 and handle 3 such that thecompression spring can always return the lever 3 to the startingposition shown. The lever 2 comprises three depressions for fingers tobe placed in such that it can be comfortably operated by the fingers ofthe same hand that also holds the handle 3.

Two cylindrical cartridges 4 are arranged side-by-side inside the device1 and contain the starting components (not shown) that are used toproduce the mixing ware. Moreover, feed plungers (not shown in FIG. 1)are arranged on the rear side in the cartridges 4 (on the right inFIG. 1) and can be shifted in longitudinal direction. The feed plungersare connected, on their rear side (on the right in FIG. 1), to two rods6 or the rods 6 touch against the rear side of the feed plungers. Therods 6 are connected to each other through a yoke 7. The purpose of therods 6 is to push the feed plungers in the cartridges 4 to the front endof the cartridges 4 (on the left in FIG. 1) without the yoke touchingagainst the rear-side opening of the cartridges 4 and thus preventing afurther motion of the rods 6 into the inside of the cartridges 4 andthus a further motion of the feed plungers in the direction of the frontside of the cartridges 4 (on the left in FIG. 1).

Moreover, the yoke 7 is connected to a gear rack 8, whereby the cogs ofthe gear rack 8 comprise a steep flank (in the direction of the frontside—on the left in FIG. 1) and a shallow flank (in the direction of therear side—on the right in FIG. 1). Alternatively, the yoke 7 can just aswell be formed by a blade that connects the rods 6 to the gear rack 8and cut through the walls of the cartridges 4 when the yoke 7 and thefeed plungers are being driven towards the front. Said design isadvantageous in that the device 1 can be designed more compact, sincethe rods 6 can then be made significantly shorter, whereby the gear rack8, in its starting position, then is arranged further in the directionof the front side of the device 1, but it is a disadvantage that alarger mechanical force needs to be exerted in order to have the bladesof the yoke cut through the walls of the cartridges 4. Moreover, bladesof this type cannot be manufactured from plastics. Therefore, the designshown, having the wide yoke 7, is preferred.

The cogs of the gear rack 8 are engaged by a snap-in locking means 9that is connected, in mobile manner, to the lever 2 by means of a shaftand that is mounted elastically sprung against the cogs of the gear rack8. The snap-in locking means 9 engages, by its front edge, the steepflanks of the cogs of the gear rack 8 when the lever 2 is rotated and/ortilted by moving the lever in the direction of the handle 3, since theshaft about which the lever 2 is rotated is situated below theconnection to the snap-in locking means 9. Accordingly, the upper partof the lever 2 tilts in the opposite direction from the lower part ofthe lever 2, by which the lever is being held.

As a result, the gear rack 8 is driven towards the front (to the left inFIG. 1) and, by means of the gear rack 8, the yoke 7 and the rods 6 andthus the feed plungers in the cartridges 4 are driven towards the frontsuch that the starting components are expelled from the cartridges 4towards the front. When the lever 2 is released or no pressure orinsufficient pressure is exerted any longer on the lever 2 by the handof the user, the spring mechanism of the lever 2 ensures that thesnap-in locking means 9 moves in the direction of the rear side of thedevice 1. Concurrently, the snap-in locking means 9 is tilted againstthe lever 2 and slips over the shallow flanks of the cogs of the gearrack 8 such that the gear rack 8 is not being moved in the direction ofthe rear side of the device 1 (on the right in FIG. 1).

Due to said spring mechanism of the snap-in locking means 9, the nextpressing or pulling of the lever 2 towards the handle 3 causes thesnap-in locking means 9 to engage cogs in the gear rack 8 that arearranged further back (further on the right in FIG. 1). As a result,each stroke of the lever 2 can push the gear rack 8 and thus the rods 6and the feed plungers a few cogs and/or cog lengths further down in thedirection of the front side of the device 1.

The lever 2 is connected, additionally, to a sprocket wheel 10 that isalso rotated along when the lever 2 is rotated. Cogs are arranged on aside surface of the sprocket wheel 10 and engage the cogwheels of a gear(not shown in FIG. 1). Said gear drives mixing vanes (not shown inFIG. 1) that can rotate on a rotary shaft (not shown in FIG. 1) in amixing space 12. The mixing space 12 is connected to the internal spaceof the cartridges 4 by means of a connection 14 such that, uponpropulsion of the feed plungers, the starting components are guided fromthe cartridges 4 via the connection 14 into the mixing space 12.

The rotation of the mixing vanes mixes the starting components in themixing space 12 and conveys them in the direction of a dispensing tube16 on the front side of the device 1 and finally expels them through thedispensing tube 16. Using a free-wheel clutch (not shown in FIG. 1), themixing vanes can rotate in the mixing space 12 in one direction and/orin one direction of rotation only. Accordingly, the mixing vanes do notrotate along with the motion of the lever 2 towards the startingposition that is attained by the compression spring between the lever 2and the handle 3. The gear having a suitable transmission ratio, themixing vanes rotate two to five times about the rotary shaft upon a fullstroke of the lever 2. Exemplary designs of the gear and device forfree-wheeling, and/or of the free-wheel clutch are described in FIGS. 2to 4, which also explain their mode of working in more detail.

Initially, the cartridges 4 are closed by a valve element 18 that isarranged, such that it can be rotated, as a tube section, in which thepart of the mixing space 12 facing the connection 14 is arranged. Thevalve element 18 comprises two openings (not shown) that can be made tooverlap with the openings of the connection 14. For this purpose, thevalve element 18 can be rotated by means of a valve lever 20. The valvelever 20 extends through a gap in the wall of the mixing space 12.

The entire assembly is arranged in a housing 21 and is manufactured fromplastics. The spring elements and compression springs can just as wellbe manufactured from metal. An upper part of the housing 21 is shown inFIG. 1 to be folded open towards the top in order to afford a view intothe inside of the device 1. The valve lever 20 of the valve element 18projects through a slit 22 in the housing 21. In operation, the housing21 is closed and all moving parts are thus covered. In order to get thedevice 1 and/or the cementing pistol 1 ready, the valve lever 20 isrotated first and thus the cartridges 4 are being opened towards themixing space 12. Subsequently, the lever 2 is operated (pressed)repeatedly and the starting components of the cement in the cartridges 4are thus being pressed into the mixing space 12 where they are mixed.Due to the pressure from the cartridges 4 and by means of the propulsionby the mixing vanes in the mixing space 12, the cement mixture is mixedand expelled towards the front through the dispensing tube 16 and can beapplied in this location.

FIG. 2 shows a schematic perspective partial view of a device accordingto the invention. The device 1 is shown without its housing in FIG. 2and the detail focuses on the essential parts of the drive of thedevice. The device comprises two cartridges 4 arranged such as to beparallel to each other, of which only one is drawn in FIG. 2. The secondcartridge has not been drawn to afford a better view of the gear. Thedevice resembles the one according to FIG. 1, whereby the present designuses, instead of the gear rack, a simple smooth cylindrical clamp rod 28that is engaged by a tiltable jamming disc 29 having a jamming opening,instead of by the snap-in locking means. Accordingly, the jamming disc29 comprises a jamming opening arranged in the centre through whichextends the clamp rod 28, whereby the internal diameter of the jammingopening is larger than the external diameter of the clamp rod 28 suchthat the jamming disc 29 can be inclined on the clamp rod 28 and thusthe jamming opening can jam with the clamp rod 29. Clamp rods 28 of thistype in cementing pistols and cementing skeleton pistols are known.

The jamming disc 29 is connected to a lever 2 such that it can be tiltedabout an axis and/or rotated, whereby the lever 2 can be rotatedmanually on the underside (not shown). A spring 30 transfers the jammingdisc 29 into a sliding (not jammed) position when the lever 2 is notbeing operated. When the lever 2 is moved, i.e. when the part of thelever 2 shown in FIG. 2 is moved towards the front (towards the righttop in FIG. 2), the jamming disc 29 jams with the clamp rod 28. As aresult, the clamp rod 28 is pushed towards the front (towards the righttop in FIG. 2).

The clamp rod 28 is connected by means of a yoke (not shown) to two rods6 of which only one rod 6 is shown in FIG. 2. Accordingly, when theclamp rod 28 is moved towards the front, the rod 6 also moves towardsthe front and pushes two feed plungers 32 into the cartridges 4, whichare arranged in parallel, which causes the content of the cartridges 4to be pressed towards the front out of the cartridges 4 into aconnection 14 and from there into a mixing space 12.

A sprocket wheel 10 is fastened to the lever 2 and rotates when thelever 2 is rotated. A rotary shaft 33 is arranged in the mixing space12, mounted such that it can rotate, and has mixing vanes (not shown inFIG. 2) arranged on it that can rotate about the rotary shaft 33 in themixing space 12. The rotary shaft 33 can be driven by the sprocket wheel10 by means of a gear. The sprocket wheel 10 is engaged by a first smallcogwheel 34 of the gear that is connected, by a shaft, to a secondlarger cogwheel 36 of the gear. The second larger cogwheel 36 finallyengages a third small cogwheel 38 that is fastened to the rotary shaft33. As a result of said transmission, the rotary shaft 33 rotatesapproximately three times about its own axis upon a full stroke of thelever 2 and thus upon a rotation of the sprocket wheel 10 by approx.45°. The mixing vanes rotate accordingly in the mixing space 12.

A free-wheel clutch and/or a sprung rotating clutch is arranged in therotary shaft 33 between the third cogwheel 38 and the mixing space 12.The spring mechanism 40 for this purpose can be seen on the rotary shaft33. The free-wheel clutch and/or the sprung rotating clutch isimplemented through two interlocked circular discs 42, 44 engaging eachother that are pushed onto each other by the spring mechanism 40. Flanksof the cogs of the circular discs 42, 44 differing in slope depending onthe direction of rotation, attain a preferential direction of therotation of the part of the rotary shaft 33 that extends into the insideof the mixing space 12.

The openings of the connection 14 to the mixing space 12 can be closedand opened by means of a valve element analogous to the one according toFIG. 1. The valve element can be rotated in a slit 22, and thus can beopened and closed, through a valve lever 20. The working mechanism ofthe device according to FIG. 2 is the same as the working mechanism ofthe device 1 according to FIG. 1. Upon each stroke of the lever 2, thefeed plungers 32 are propelled further into the inside of the cartridges4. Concurrently, the same motion of the lever 2 rotates the rotary shaft33 and thus rotates the mixing vanes in the mixing space 12. Due to therotation of the mixing vanes, the content of the mixing space 12 isbeing mixed and extruded through an exit opening (not shown in FIG. 2)out of the device.

FIG. 3 shows a schematic perspective and partially sectioned view of thedevice according to the invention according to FIG. 2, in which the twomutually-engaging, interlocked circular discs 42, 44 of the free-wheelclutch and/or sprung rotary clutch and the mixing vanes 46 can be seenwell. Moreover, it can be seen through the section made how the valveelement 18 rests in and/or touches against the walls of the mixing space12. A spring 47 pushes the right (front) circular disc 44 onto the left(rear) circular disc 42. The mixing vanes 46 are arranged inclined onthe rotary shaft 33 in the same sense of orientation with respect to therotary shaft 33 such that a rotation of the rotary shaft 33 propels themixing ware in the mixing space 12 (towards the right in FIG. 3).

When the upper edge of the (third) cogwheel 38 rotates into the imageplane, the friction of the shallow flanks of the circular discs 42, 44is insufficient for the right circular disc 44 to rotate along with theleft circular disc 42. The circular discs 42, 44 slip over each otherand the rotary shaft 33 arranged in the mixing space 12 does not rotatealong.

When the lower edge of the (third) cogwheel 38 rotates into the imageplane, the steep (perpendicular) flanks of the circular discs 42, 44engage each other such that the right circular disc 44 rotates alongwith the left circular disc 42. The rotary shaft 33 arranged in themixing space 12 rotates along with the mixing vanes 46. Accordingly, arepeated motion of the lever 2 and thus of the gear-mediated rotarymotion of the rotary shaft 33 in front of the mixing space 12 resultsjust in an unidirectional rotation of the rotary shaft 33 in the mixingspace 12 and thus of the mixing vanes 46. Accordingly, the mixing vanes46 always drive the mixing ware in the mixing space 12 towards thedispensing opening (on the right in FIG. 3).

The valve element 18 comprises a round valve opening 48 in the form of apassage through the wall of the tube-shaped valve element 18. The valveopening 48 rotates along with the valve element 18. When the valveelement 18 is rotated into an appropriate position, as shown in FIG. 3,the valve opening 48 overlaps with the access to the connection 14and/or to the cartridge connector 14. A second valve opening (not shown)then establishes an opening to the connection 14 of the second cartridge(not shown in FIG. 3). As a result, the two cartridges are openedtowards the mixing space 12 and the starting components can be conveyedfrom the cartridges into the mixing space 12.

According to another embodiment of the invention that can be consideredto be a variant of the design according to FIG. 3, the invention canprovide the third cogwheel 38 and the left circular disc 42 to comprisea cylindrical bushing, and the rotary shaft 33 to extend through thesebushings such that the third cogwheel 38 and the left circular disc 42are arranged on the rotary shaft 33 such that they can be shifted alongthe symmetry axis of the rotary shaft 33. The rotary shaft 33 is thenformed in the direction of the yoke as a spindle having a thread. Aninternal thread is provided in the yoke in the form of a screw nut bymeans of which the rods and thus the feed plungers are propelled suchthat the yoke and thus the rods and the feed plungers are pulled in thedirection of the connections 14 of the cartridges to the mixing space 12by the rotation of the spindle. Moreover, the third cogwheel 38 and theleft circular disc 42 are spring-mounted in the direction of the rightcircular disc 44 by a compression spring between the thread of thespindle and the third cogwheel 38. The third cogwheel 38 and the leftcircular disc 42 are preferably provided as a single part. For thispurpose, the third cogwheel 38 preferably has a larger height than thedrive cogwheel (the second cogwheel) engaging the third cogwheel 38 suchthat the third cogwheel 38 can glide on the drive cogwheel without thefull height of the cogwheel no longer being usable any more. For thispurpose, it is sufficient if the third cogwheel 38 is higher than thedrive cogwheel by the height of the cogs of the circular discs 42, 44.As a result of said design, the rotating rotary shaft 33 of the mixingvanes 46 can also be used as drive spindle for propulsion of the feedplungers.

FIG. 4 shows another schematic perspective and partially sectioned viewof a device according to the invention. The design is identical to theone according to FIGS. 2 and 3, whereby a conical cogwheel 39 instead ofthe usual cogwheels is incorporated such that the direction of rotationcan be reversed by the gear. As a result, the cogs of the sprocket wheel(not shown in FIG. 4) can just as well be arranged on the front side ofthe sprocket wheel. For this purpose, the other cogwheels, in part orall of them, are also provided as conical cogwheels (not shown).Preferably, the sprocket wheel also comprises an inclined surface andthus forms a conical sprocket wheel.

Static shearing elements 49 that do not rotate along with the rotaryshaft 33 are arranged in the mixing space 12. The purpose of saidshearing elements 49 is to cut the mixing ware, which is being propelledtowards the front (to the right top back in FIG. 4) perpendicular to theconveying direction and to thus improve the mixing. A series of fiveshearing elements not shown in FIG. 4 is arranged with mirror symmetryon the opposite side of the rotary shaft 33 in the mixing space 12. As aresult, the rotary shaft 33 is supported as in a bearing in the mixingspace 12 by the shearing elements 49, which end in cylindrical shellsegments.

The purpose of the spring mechanism 47 is to push the right (front)circular disc 44 onto the left (rear) circular disc 42. When the upperedge of the conical cogwheel 39 rotates in counter-clockwise directionwith respect to the rotary shaft 33 (viewed from the back—viewed fromleft bottom front in FIG. 4), the friction of the shallow flanks of thecircular discs 42, 44 is insufficient for the right circular disc 44 tomove along with the left circular disc 42. Rather, the circular discs42, 44 slip over each other and the part of the rotary shaft 33 arrangedin the mixing space 12 and the mixing vanes 46 do not rotate.

When the conical cogwheel 39 rotates in clockwise direction (viewed fromleft bottom front in FIG. 4), the steep (perpendicular) flanks of thecircular discs 42, 44 engage each other such that the right circulardisc 44 rotates along with the left circular disc 42. The rotary shaft33 arranged in the mixing space 12 rotates along with the mixing vanes46. Accordingly, the repeated motion of the lever 2 and thus therepeated gear-mediated rotary motion of the rotary shaft 33 in front ofthe mixing space 12 result(s) just in a unidirectional rotation of therotary shaft 33, and thus of the mixing vanes 46, in the mixing space12. Accordingly, the mixing vanes 46 always drive the mixing ware in themixing space 12 towards the dispensing opening.

FIG. 5 shows a schematic side view of a functionally essential part of afurther device according to the invention and/or a cementing gunaccording to the invention. This device also is shown in the absence ofa housing. A part of the device is shown sectioned in the depiction ofFIG. 5. Sectioned surfaces are shown hatched in FIG. 5.

The device is operated by means of a spring-mounted pin 52 that ismobile in longitudinal direction, instead of a lever. The springmechanism is attained by means of a spring 54 that is fastened between abracket 55 on the housing (not shown) and a bracket 56 on a button 58 ora key 58. When the button 58 is pushed in the direction of the bracket55, the compression spring 54 is being compressed and takes up energy.Releasing the pressure, the pin 52 is pushed to the front again (to theleft in FIG. 5) by the button 58.

In the rear region arranged inside the housing, cogs 60 are arranged onone side on the pin 52 such that the pin 52 forms a gear rack 52 in thisregion. Said gear rack 52 is arranged to be axially mobile with respectto a cogwheel 62 such that the cogs 60 of the gear rack 52 and/or pin 52engage the cogs of the cogwheel 62. The cogwheel 62 is connected bymeans of its shaft to a free-wheel clutch 64 that ends in an outersprocket wheel. The free-wheel clutch 64 rotates the outer sprocketwheel with the cogwheel 62 only if the cogwheel 62 rotates in clockwisedirection with respect to the direction of view of the observer of FIG.5, i.e. when the pin 52 is pushed towards the back (to the right in FIG.5). Free-wheel clutches 64 of this type are known, for example, frombicycles, but can be designed very simply for the present purpose, sincethey do not need to have particularly easy-running idling properties.

The outer sprocket wheel of the free-wheel clutch 64 engages a cogwheel65 that is arranged on a cogwheel shaft such that it can rotate. Aconical cogwheel 66 is arranged on said cogwheel shaft and rotates alongwith the cogwheel 65. The conical cogwheel 66 is arranged in front ofthe cogwheel 65, with respect to the viewing plane, in FIG. 5. A secondconical cogwheel 67, arranged orthogonally, engages the conical cogwheel66 and drives a rotary shaft 68, 70. Accordingly, the rotary shafts ofthe conical cogwheels 66, 67 are perpendicular to each other. Theinclination of the cone jacket surface of the conical cogwheels 66, 67is inclined at an angle of 45° with respect to the rotary shaft thereof.

The second conical cogwheel 67 is arranged on the rear rotary shaft 68.The front rotary shaft 70 is arranged in a mixing space 72 that isbordered by mixing space walls 72 and is shown in cross-section in FIG.5. For this purpose, the rotary shaft 68, 70 is guided through a sealinto the mixing space 72, in which the rotary shaft 68, 70 is supportedas in a bearing such that it can rotate. Mixing vanes 74 are arranged onthe front rotary shaft 70 and rotate in the mixing space 72 when therotary shaft 68, 70 rotates. The mixing vanes 74 are inclinedappropriately with respect to the plane perpendicular to the rotaryshaft 70 such that the mixing vanes 74 drive a mixing ware in the mixingspace 72 (to the left in FIG. 5) towards the front, when the rotaryshaft 70 is driven by the pin 52 being pressed and/or by a motion of thepin 52 to the right in FIG. 5.

To improve the mixing of the mixing ware, perpendicular shearingelements 76 are arranged in the mixing space 72 and extend asrectangular discs perpendicularly from the mixing space wall 72 in thedirection of the rotary shaft 70. The shearing elements 76 cut throughthe cement paste (the mixing ware) that is being driven in the directionof a front dispensing opening (not shown in FIG. 5).

The pin 52 is connected on its rear side to a lever 78 by means of arotatable shaft. The lever 78 is supported as in a bearing by a shaft 80such that it can be rotated and/or tilted with respect to the housing.The lever 78 can be designed in telescoping manner in order to be ableto move along on the linear motion of the pin 52. A snap-in lockingelement 82 is connected to the lever 78 on the opposite side of thelever 78 by means of a shaft such that it can rotate. The snap-inlocking element 82 is pressed, by a leaf spring 84, against a rod 86bearing cogs 88.

The cogs 88 of the rod 86 have a perpendicular flank, which points tothe right in FIG. 5, and a shallow flank, which points to the left inFIG. 5. The snap-in locking element 82 engages the perpendicular flanksof the cogs 88 and glides over the shallow flanks of the cogs 88. As aresult, upon a motion of the pin 52 in the direction of the rear side ofthe device (to the right in FIG. 5), the rod 86 is pushed in thedirection of the front side of the device (to the left in FIG. 5) by thelever 78 and the snap-in locking element 82.

The rod 86 pushes onto a feed plunger 90 that is arranged in a cartridge92 that is filled with one of the starting components for the mixingware and/or with the bone cement, and that is connected to the mixingspace 72. The rod 86 can just as well be fastened to the feed plunger90. A second cartridge (not shown) is situated right before or behindthe cartridge 92 shown in cross-section in FIG. 5, and is arranged to beparallel to the first cartridge 92 and has a linearly mobile feedplunger (not shown) arranged in it. The design of the two parallelcartridges 92 is identical in this context. The rod 86 is shaped in theway of a yoke such that the feed plunger of the front (second cartridge)is also driven by the rod 86. The front cartridge also exits into themixing space 72.

Due to the propulsion of the rod 86 and the feed plungers taking placein separate pushes, the components are conveyed out of the cartridges 92into the mixing space 72 and are mixed therein by means of the staticshearing elements 76 and the rotating mixing vanes 74, and are driven tothe front by the rotating mixing vanes 74. Lastly, the ready-mixedmixing ware (the medical cement) is expelled to the front out of thedevice and applied.

It is preferred according to the invention to have at least one closure(not shown) that can be opened manually or one valve element (not shown)that can be opened manually arranged on the openings or in the openingsbetween the cartridges 92 and the mixing space 72, by means of which themixing space 72 is separated from the two cartridges 92. The closureand/or the valve element, as the case may be, closes the content of thecartridges 92 off from the outside and renders the device well-suitedfor storage of the starting components (or of the cartridge contents, asthe case may be).

Instead of cogwheels and conical cogwheels, friction wheels and conicalfriction wheels can be used just as well in all embodiments.

The features of the invention disclosed in the preceding description andin the claims, figures, and exemplary embodiments, can be essential forthe implementation of the various embodiments of the invention bothalone and in any combination.

LIST OF REFERENCE NUMBERS

-   1 Device/cementing gun-   2 Lever-   3 Handle/pistol handle-   4 Cartridge-   6 Rod-   7 Yoke-   8 Gear rack-   9 Snap-in locking means-   10 Sprocket wheel-   12 Mixing space-   14 Connection/cartridge connector-   16 Dispensing tube-   18 Valve element-   20 Valve lever-   21 Housing-   22 Slit-   28 Rod-   29 Jamming rod-   30, 47 Spring-   32 Feed plunger-   33 Rotary shaft-   34, 36, 38 Cogwheel-   39 Conical cogwheel-   40 Spring mechanism-   42, 44 Circular disc-   46 Mixing vanes-   48 Valve opening-   49 Shearing element-   52 Pin/gear rack-   54 Spring-   55, 56 Bracket-   58 Button/key-   60, 88 Cog-   62 Cogwheel-   64 Free-wheel clutch-   65 Cogwheel-   66, 67 Conical cogwheel-   68 Rear rotary shaft-   70 Front rotary shaft-   72 Mixing space wall-   74 Mixing vanes-   76 Shearing element-   78 Lever-   80 Shaft-   82 Snap-in element-   84 Leaf spring-   86 Rod-   90 Feed plunger-   92 Cartridge

The invention claimed is:
 1. A manually drivable device for mixing of apasty mixing ware from at least two fluid starting components, saiddevice comprising: at least two cartridges containing the fluid startingcomponents or at least two connectors for at least two cartridgescontaining the fluid starting components, whereby feed plungers areprovided in the cartridges for expelling the starting components fromthe cartridges; a mixing space for the mixing of the starting componentsthat is connected to the cartridges or connectors for the cartridgessuch that the starting components are guided into the mixing space whenthe starting components are expelled from the cartridges by the feedplungers, whereby mixing vanes are provided in the mixing space and aremounted in the mixing space such that they can rotate; a lever that canbe rotated about a pivot point and can be operated manually foroperation of the device or a pin that can be shifted in the longitudinaldirection and can be operated manually in order to operate the device; agear connected to the lever or pin, whereby the gear is appropriatelyconnected to the rotatable mixing vanes in the mixing space such thatthe mixing vanes can be rotated in the mixing space upon a motion of thelever or pin mediated by the gear, wherein a clutch is provided in theconnection of the gear to the mixing vanes, whereby the clutch allowsthe mixing vanes to rotate in one direction of rotation and prevents orreduces rotation in the opposite direction of rotation; and a facilityfor propelling the feed plungers in the cartridges, appropriatelyconnected to the lever or pin such that the feed plungers can bepropelled in the cartridges upon a motion of the lever or pin, such thatthe motion of the lever or pin drives the rotation of the mixing vanesin the mixing space and the motion of the feed plungers into thecartridges.
 2. The device according to claim 1, wherein the mixing vanesare inclined consistently with respect to the axis about which themixing vanes rotate in the mixing space such that the rotation of themixing vanes in the mixing space causes the mixing ware to be propelledin the mixing space.
 3. The device according to claim 1, wherein thegear is force-locking and/or form-fitting.
 4. The device according toclaim 1, wherein the gear comprises at least one tooth lock washer, atleast one friction disk, at least one cogwheel, at least one worm wheeland/or at least one friction wheel by means of which force and/or torqueis transmitted.
 5. The device according to claim 1, wherein the gear isa cogwheel gear, a friction wheel gear, a conical wheel gear, a contrategear, a worm gear or a combination of said gears.
 6. The deviceaccording to claim 1, wherein the mixing vanes are arranged on a rotaryshaft that is mounted such as to be rotatable, whereby the rotary shaftextends out of the mixing space, and the rotary shaft is connected tothe gear such that the rotary shaft with the mixing vanes can be rotatedin the mixing space by means of a motion of the lever or pin.
 7. Thedevice according to claim 6, wherein the clutch is provided in therotary shaft.
 8. The device according to claim 1, wherein the clutch isa sprung rotating clutch provided in the connection from the gear to themixing vanes.
 9. The device according to claim 1, wherein the facilityfor propelling the feed plungers in the cartridges is a clamp rod havinga tiltable jamming opening or a gear rack having aunidirectionally-acting snap-in locking means, whereby the jammingopening or the snap-in locking means is connected to the lever or thejamming opening or the snap-in locking means is connected to the pin.10. The device according to claim 1, wherein at least onemanually-opening valve element or manually-opening closures is/arearranged in the connection between the mixing space and the cartridgesor in the connectors for the cartridges.
 11. The device according toclaim 1, wherein the device comprises a handle for holding the device byone hand, whereby the lever or the pin or an operating element formanual operation of the lever or pin is arranged appropriately in theregion of the handle such that the lever or pin or operating element canbe operated by the same hand that holds the device by the handle. 12.The device according to claim 1, wherein the mixing space comprises adispensing opening for application of the mixing ware on a side oppositefrom the connection to the cartridges.
 13. The device according to claim1, wherein static shearing elements for mixing of the mixing ware arearranged in the mixing space.
 14. The device according to claim 1,wherein a circular arc or circular arc section is arranged on the leverand has on its front face or its side surface a driving row of cogs or afriction surface arranged by means of which a cogwheel or friction wheelof the gear can be driven or in that a serration or a friction surfaceis arranged on the pin by means of which a cogwheel or friction wheel ofthe gear can be driven.
 15. The device according to claim 1, wherein thegear comprises an appropriate transmission ratio such that, upon a fullmotion of the lever or pin, the mixing vanes perform at least 2 turns inthe mixing space.
 16. The device according to claim 1, wherein thefacility for propelling the feed plungers in the cartridges isappropriately connected to the lever or pin such that, upon a fullmotion of the lever or pin, the feed plungers are propelled in thecartridges by at least 1 mm.
 17. The device according to claim 1,wherein the facility for propelling the feed plungers in the cartridgesis appropriately connected to the lever or pin such that the feedplungers expel at least 90% of the starting components from thecartridges upon 5 to 25 full motions of the lever or pin.
 18. A methodfor the mixing of fluid starting components, said method being carriedout with the device according to claim 1, said method comprising:tilting the lever or moving the pin of said device in the longitudinaldirection; a force produced by tilting the lever or moving the pinpropelling the feed plungers in the at least two cartridges and pressingthe starting components contained in the cartridges into the mixingspace by means of the feed plungers; and the force produced by tiltingthe lever or moving the pin rotating the mixing vanes in the mixingspace, whereby the transmission of the force of the lever or pin forrotating of the mixing vanes is effected by means of the gear whereinthe lever or pin, after being moved, is restored to a starting positionby a restoring element, whereby the feed plungers are not moved and themixing vanes are not rotated during said restoration to the startingposition.
 19. The method according to claim 18, wherein the rotating ofthe mixing vanes in the mixing space mixes the starting components inthe mixing space and conveys them in the direction of a dispensingopening.
 20. The method according to claim 18, wherein the gear isdriven by means of a sprocket wheel or friction sprocket wheel on thelever or a row of cogs or a friction surface on the pin.
 21. The methodaccording to claim 18, wherein the motion of the pin or lever isrepeated in order to empty the cartridges by at least 90%.
 22. Themethod according to claim 18, wherein the gear transmits a full strokeof the lever or pin into at least 2 turns of the mixing vanes in themixing space.